High frequency germline acquisition of ecotropic MuLV proviruses in SWR/J-RF/J hybrid mice

Area of Science:

• Genetics
• Virology
• Mouse Models

Background:

• RF/J mice possess three endogenous ecotropic murine leukemia proviruses (Emv-1, Emv-16, Emv-17).
• Emv-16 and Emv-17 are linked and associated with high viremia in backcrossed mice.

Purpose of the Study:

• Investigate the acquisition of new germline proviruses in progeny derived from female virus carriers.
• Characterize the susceptibility of specific mouse strain combinations to proviral acquisition.

Main Methods:

• Derivation of an SWR/J strain congenic for Emv-16 and Emv-17.
• Genetic crosses to analyze proviral acquisition patterns.
• Comparison of proviral acquisition frequency with P element acquisition in Drosophila melanogaster.

Main Results:

• Progeny from female virus carriers frequently acquired new germline ecotropic proviruses.
• Specific strain combinations exhibit high susceptibility to early developmental virus infection and proviral integration.
• Proviral acquisition frequency was comparable to P element acquisition rates in Drosophila.

Conclusions:

• Mouse strain combinations can be highly susceptible to germline proviral acquisition during early development.
• These susceptible hybrids provide a model for studying virally induced mutations at the molecular level.
• The findings highlight the dynamic nature of retroviral elements in mammalian genomes.